1. Field of the Invention
This invention relates to insecticides, to insecticidal formulations, and to processes for the protection of articles from insect attack. More particularly, this invention is directed to insecticides and the like having improved persistency or duration of protective effect. Additionally, this invention concerns such formulations and processes wherein microencapsulated insecticides are modified with type B gelatin so as to improve the adherence of such microcapsules to the articles to be protected from insects to improve persistency concomitantly.
2. Discussion of the Prior Art
Microencapsulation through an interfacial polymerization process is known. Thus, U.S. Pat. Nos. 3,270,100 issued to Jolkovski, et al and 3,577,515 issued to Vandegaer, for example, disclose interfacial polymerization techniques for the reduction of microencapsulated liquids.
U.S. Pat. No. 3,959,464 issued to DeSavigny discloses microencapsulated methyl and ethyl parathions for use as insecticides. U.S. Pat. No. 4,056,610 issued to Barber, et al, discloses microencapsulated insecticides comprising microcapsules having polyurea shells including as an integral part of the shell wall a photo-stable ultraviolet light absorbent compound.
It has been proposed to employ "stickers" with microencapsulated insecticides to improve their persistency. Thus, acrylic species have been investigated for such use. See Pesticide Science 4, pp. 51-57 (1973). Additionally, the use of non-gelatinous proteins such as casein, albumin and animal or fish glue has been proposed. It has not been suggested that improvement in persistency may be accomplished through the association of type B gelatin with microencapsulated insecticides.